The present invention relates generally to a dust cap for protecting a wheel bearing from contamination, and, more particularly, to a dust cap that can be quickly removed to facilitate servicing of the wheel on race cars during a pit stop.
Sprint cars and smaller racing cars are provided with front, non-driven ground engaging wheels that are mounted by bearings on a spindle to permit rotation of the front tires with a minimum of friction to enhance the performance of the race car. The wheel is formed with a central opening that permits access to the spindle and the bearings mounting the wheel on the spindle, allowing the front wheel to be removed rapidly and replaced during a pit stop while the race is being conducted. This central opening is covered by a dust cap that is typically clipped to the wheel or to the wheel hub or fastened with pins, bolts or other fasteners. As a result, the dust cap requires a significant amount of time to remove before access to the spindle or bearings.
U.S. Pat. No. 3,170,733, granted to Robert Lamme on Feb. 23, 1965 discloses a wheel cover with an adapter held onto the wheel by the wheel lug nuts. The ornamental wheel cover includes a center cylinder with outside threads that screw onto inside threads on the center cylinder of the adapter. In U.S. Pat. No. 5,464,277, issued to Kevin Redd on Nov. 7, 1995, describes a bolt-on adapter for a decorative wheel ornament. The adapter is held onto the wheel by bolts, while the ornament has a cylindrical center with inside threads that match outside threads on the center cylinder of the adapter. U.S. Pat. No. 6,203,204, granted to Robert Carmichael on Mar. 10, 2001, uses a wheel bearing cap to hold a sensor detecting rotational movement of the wheel. An annular retaining ring on the wheel bearing cap is described only as being sealed into the annular groove in the wheel bearing outer ring as a support flange on the wheel bearing cap engages a mounting surface on the bearing outer ring.
None of these prior art references teach a wheel bearing cap that is operable to seal the central opening of the wheel in which the bearings are mounted against the entry of dirt and water, while providing an ability to remove the dust cap quickly to reduce the time of the pit stop for a race car requiring a front wheel change. The dust cap needs to prevent the entry of dirt into the wheel bearings to permit the bearings to function properly in rotatably mounting the front wheel to the front axle of the race car. However, a quick removal of the dust cap to gain access to the axle spindle and permit the quick removal of the front wheel to reduce the time the race car is in the pit being serviced is an important feature for race cars.
Some dust caps are press fit into the wheel or mounted with spring clips or spiral locks that require tools to affect the release of the dust cap from the wheel. If any difficulty is encountered in the removal of the dust cap, typically the dust cap is forcibly removed, resulting in an imperfect seal between the dust cap and the wheel when the dust cap is replaced on the wheel that has been newly mounted on the race car. In such situations, dirt is free to enter into the front wheel bearings to cause an increase in friction between the wheel and the axle spindle to the possible point of destruction of the front wheel bearings, which would eliminate the race car from the race being conducted.
The existing mounting of dust caps for the wheel bearings on racing cars does not provide a seal that prevents the introduction of water and/or dirt into the wheel bearings. Accordingly, the lubricant of choice that is used to lubricate the bearings is grease, which is a less effective lubricant than a more viscous oil lubricant.
Accordingly, it would be desirable to provide a dust cap that would provide an easily removable feature without damage to the dust cap, while maintaining a watertight and dirt tight seal between the dust cap and the wheel of the racing car.